Method of and apparatus for the treatment and use of liquid fuels



Jan. 2, 1934. E. A. BURROWS 1,941,968

METHOD OF AND APPARATUS FOR THE TREATMENT AND USE OF DIQUID FUELS FiledMarch 15, 1930 I5 Sheets-Sheet l &

OIL VAPOIRS F951 OIL FIG. I.

Jan.2,l934. E W L94L968 METHOD OF AND APPARATUS FOR THE TREATMENT ANDUSE OF LIQUID FUELS Filed March 15, 1930 3 Sheets-Sheet 2 Jan. 2, 1934.E, BURROWS 1,941,968

METHOD OF AND APPARATUS FOR THE TREATMENT AND USE OF LIQUID FUELS FiledMarch 15, 1930 3 Sheets-Sheet 3 Patented jan. 2, 1934 UNITED STATESMETHOD OF AND APPARATUS FOR THE TREATMENT AND USE OF LIQUID FUELSEastman A. Burrows, Chicago, Ill., assignor of one-half to Thomas D.Campbell,

Mont.

Hardin,

7 Application March 15, 1930. Serial No. 436,014

4 Claims.

This invention relates to systems for the distillation or other heattreatment of liquid fuel such as hydrocarbon oils by what may be termedwaste heat derived from the combustion of a portion of the fuel. Inaccordance with one form of the invention, oil, which may be of arelatively low grade and may, for example, be a comparatively heavypetroleum, is subjected to distillation, with or without conversion, bythe application of the waste heat of the flue gases from a power plant,or similar heat-consuming system, and is then separated into its lightermarketable constituents and its heavier components, the latter beingutilized while hot as the fuel for the development of the heat requiredby the power plant, or other system.

A feature of the invention is in the economy of operation which itaffords for the generation of power by heat, or the utilization of fuelfor other purposes, such as in the firing of kilns for making brick orthe like, or for use in furnaces of various sorts. Heat which wouldotherwise be largely wasted or used to poorer advantage in systems ofthe type mentioned may be employed for the purpose of treating acomparatively cheap hydrocarbon oil to form and eliminate certain morevaluable components while the heavy, less valuable constituents may beburned to generate the necessary heat. In this way the enhancement invalue of the lighter components of the oil will offset in part or infull the initial cost of the crude or other oil used in the process andwill in effect supply fuel to the main unit of the system at small oreven a negative cost.

A number of factors enter in to make the combination system particularlyeffective for the pur poses mentioned. In the first place the fuel whichis burned to generate heat for power or other purposes may be used underfavorable conditions so that high efiiciency is obtainable. For example,where power is to be generated the boilers may be fired at acomparatively high temperature, which may be well over 2000 F. since thewater tubes of such a system are capable of withstanding hightemperatures. The flue gases leaving such a system may still be at atemperature as highas 1500 F., or even above, so that they are admirablysuited to the distillation of the original fuel. In the second place theimmediate transmission to the burners and utilization of the heavierproducts of the distillation while still hot enables the use of acomparatively heavy residual oil for this purpose, which wouldpractically solidify and be incapable of such use after having beenallowed to cool.

Numerous other features and advantages of the invention will appear fromthe detailed description of the same which will now be given inconjunction with the accompanying drawings, in which: Q

Figure 1 is a diagrammatic view showing the inter-relation between thevarious portions of one type of system to which the invention may beapplied.

Figure 2 is a diagrammatic View showing a modified form of furnace whichmay be advantageously employed in the system disclosed in Figure 1, and

Figure 3 is a diagrammatic View showing a modified arrangement ofapparatus as employed in a different type of system.

Referring now to Figure 1, there is disclosed a furnace of more or lessconventional form having a fire chamber or combustion zone and aneconomizer section or convection zone 11. Between the two zones, and ineffect forming a screen to divide the one portion of the furnace fromthe other, there may be advantageously provided a boiler systemcomprising a plurality of inclined tubes 12 extending between a pair ofheaders or drums 13 and 14. A fresh supply of water may be introducedinto the lower drum through a line 15 while steam may be withdrawn froma dome connected with the upper drum through a line 16.

In the economizer section 11 of the furnace there may be mounted a coil17 of any suitable construction, being formed preferably of a series ofpipe sections joined at their ends by return bends or junction boxes.The diameter and wall thickness of the pipe used in the coil will dependentirely upon the capacity of the unit and the nature of the heattreatment to which oil flowing through the coil 17 is to be subjected. Astorage container 18 may be provided to carry a supply of any suitabletype of oil, or similar hydrocarbon fuel, which may, if desired, be inthe nature of crude oil or other comparatively heavy oil. A pump 19,suitably connected to the supply tank, may serve to force the oilthrough the coil 1'7 and discharge it through a line 20 and a pressureregulating valve 21 into a chamber 22. Depending upon the treatment towhich it is desired to subject the oil, the latter may be forced throughthe coil 17 under any desired pressure, ranging from slightly aboveatmospheric to a substantial pressure of 1,000 pounds, or more.comparatively low pressure will be employed if it is merely desired todistill the oil without effecting any conversion. However, where it isdesired to produce a certain amount of cracking or destructivedistillation to effect conversion of some of the heavier constituentsinto gasoline or similar light components, a higher range, between 250pounds and 1,000 pounds, will preferably be employed. In such a case theregulating valve 21 is preferably set to effect a material reduction inpressure, which may be down to substantially atmospheric within thechamber 22.

Lighter vapors which are evolved as a result of the distillation,destructive or otherwise, may be carried over by a vapor line 23 to acondenser coil 24 and the cooled, lighter products may be collected inan accumulator drum 25 having the usual gas and liquid outlets. Heaviercomponents of the oil which are condensed or remain in liquid form inthe chamber 22 may be withdrawn through a line 26 and forced under thepressure within the chamber, or by means of a pump 27 through a line 28to burners 29. Air, or other suitable combustion supporting medium, maybe supplied to the burners through a line 30. If desired, automaticmeans may be provided for controlling the quantity of oil consumed bythe burners. For this purpose a valve 31 may be provided in the line 28and may be controlled in any suitable way by a regulator 32 in the formof a piston or diaphragm affected by the pressure of the steam in thedrum 13.

Should it be desired to supply additional heat to the coil 17 in excessof that conveyed by the flue gases passing through the screen of boilertubes 12,a branch line 33, also fed by the pump 27, may supply oil toburners 34 which receive air, or a similar combustion supporting medium,through a line 35. The burners 34 are preferably situated within aspecial chamber 36 at the bottom of the convection section of thefurnace in such a way that the coil 17 will be shielded from the director radiant heat from these burners. A valve 37 may be provided in theline 33 to regulate the quantity of oil supplied to the auxiliaryburners. The valve 37 may be automatically controlled by a regulator 38responsive to a thermostatic unit or thermocouple 39 mounted in theconvection section just below the coil 1'7. In this way additional heatmay be supplied to the coil under the direct control of the temperatureof the furnace below the coil. If desired, a further control may beeffected over the supply of fuel fed from the tank 18 through the coil17. This may comprise a regulator 40, also operated under control of thetemperature-responsive unit 39 and adapted to regulate a valve 41 in thesteam line 42 which is connected with the drum 13 and with the pump 19which forces the oil through the coil 17. In this way the quantity offuel fed into'the system, and from which the supply at the bottom of thechamber 22 is derived, may be regulated directly by the temperaturesdeveloped in the furnace. Obviously, the thermocouple or thermostaticunit 39 might be located at some other point, such as at the top of thefurnace, if desired, but its location at the point indicated serves toprovide a more effective control.

Where the fuel which accumulates in the chamber 22 is of low Baumgravity and is apt to become viscous, or even semi-solid, upon beingallowed to stand for any period of time, it will be found desirable tomaintain a certain portion of this oil in continuous circulation. Forthis purpose a line 43 may be connected to the outlet side of the pump27 to return any desired portion of the oil withdrawn from the chamberdirectly back to the same.

In the operation of the unit just described, a. temperature well above2000 F., and even as high as 2500 or 3000 F., may be maintained in thecombustion zone 10. The water tubes of the boiler system will be readilycapable of withstand,- ing these high temperatures. In such a case thewaste flue gases entering the convection zone may still have atemperature between 1500 and 1800 R, which will be sufficient to effecteither ordinary distillation or even destructive distillation of the oilin the coil 1'7.

It will be found that in the operation of the system to provide justenough heavy oil at the bottom of the chamber 22 to serve as fuel forthe power plant, a quantity of lighter components, in the nature ofgasoline, kerosene, gas oil and the like, and possibly even lubricatingstock, may be taken overhead from the chamber 22, which will besufhcient to practically pay the initial cost of the oil taken from thesource of supply 18.

In Figure 2 there is shown a slightly modified form of furnaceconstruction which may advantageously be substituted for the furnaceshown in Figure 1. Thus, it may comprise a fire chamber or combustionzone 45 adapted to be fired by a series of burners 46 supplied byoilthrough a pipe 47 connected with a supply of heavy oil developed at apoint in the associated distillation equipment corresponding to thechamber 22. A suitable control valve 48 may be provided in the line 47.Steam may be passed to the burners through a line 49. Regulation of theflame may be effected by a hand-operated or automatically controlledvalve 50. Associated with the combustion zone or furnace there may beprovided a large heating chamber 51 which is adapted to receive acertain amount of radiant heat and a considerable amount of heat ofconvection. Within this heating chamber there may be provided anysuitable type of boiler system, preferably involving a lower drum 52, anupper steam drum 53, and a series of connecting tubes 54' through whichthe water passes between the drums. In this type of boiler, considerablespace may generally be found between the front and rear banks of tubesand it is proposed to place in this space an oil heating coil 55 of anysuitable construction. This coil, as will be clear, will be shieldedbythe tubes 54 from the direct radiant heat of the burners and willmerely receive the milder convective heat of the flue gases. A pump 56,conneoted to a suitable source of oil supply, may force the oil throughthe coil 55 under any desired pressure and the heated oil maybe passedby a line 58 to an expansion zone, or simfl'ar point of the oildistillation system. The systems as a whole may, in this case, operateon substantially the same basis as that first described.

In Figure 3 there is shown a system which embodies the principles of thepresent invention in connection with the treatment of the originalliquid fuel or hydrocarbon material in a particular way and theutilization of its heavier components in connection with a brick kiln tosupply heat to the latter. Thus, thesystem may include a kiln 60 adaptedto befired by a series of: burners 61, which will raise the temperaturewithin the kiln to a suitable point, preferably between- 2500 and 3000F; Liquid fuel developed within the distillation portion of the unit maybe fed to the burners through a line 62. A down-draft: arrangement maysuitably be provided in. connec tion with the kiln and for this purposethere may be included a laterally extending flue 63 for-re moving thecombustion gases and passing them to a stack-suitablylooated, but notshown. With-- in the flue may be mounted, in any suitable way, a heatingcoil 64 adapted to absorb heatfrom the waste flue gases and impart it tothe oil or other medium passed through the coil. For this purpose a pump65- may serveto draw oil from an annular' chamber formed between a tankor drum 6E and an innercircular wall 6'7 concentric with the tank andforming an inner container there in. This oil, after being heated in thecoil 64 at any suitable pressure, may be expanded through a pressureregulating valve 68 and passed into a tube 69 which extends into thespace within the circular wall 6'7. This tube preferably has itsdischarge outlet at some distance from the bottom of the tank and isadapted to discharge the material which is now all, or substantiallyall, in vapor form against the lowermost of a series of inner baflles'70. A series of co-operating doughnut rings, or outer bafiles, '71 maybe provided to force the vapors to follow a tortuous path. A certainamount of cracked or other heavy vapors or liquids may be depositedwithin this inner chamber and will accumulate at the bottom thereoftogether with the residual material from the fresh oil which ispreferably continuously recycled, as will be described. This oil may bewithdrawn through a line '72 and may be forced by a pump '73 through acentral pipe 74 and discharged over the top of the uppermost of thebaffles '70. A portion of this oil will then be re-vaporized and thebalance will again descend to the bottom of the inner container countercurrent to the rising vapors. Fresh oil may be inroduced into the systemby means of a pump '75 and may advantageously be merged in the line '74with the heavy material which is circulated in the way mentioned. Anylight components of this fresh charge will be vaporized and strippedfrom the same by the rising, heated vapors released at the end of thetube 69.

Within the inner chamber only the heavier components will descend to thebottom to be circulated by the pump '73. All of the vapors emerging fromthe top of the inner chamber pass around a hood or bafile member '76 andinto the upper portion of the tank or drum 66. This upper portion of thetank may, if desired, be provided with suitable fractionating ordephlegmating devices, such as bubble trays, bafiie members, packingmaterial, or the like. At the top a coil '77 maybe provided and may beadapted to receive any suitable form of cooling medium, such as water,or, if desired, the fresh charge may be passed through the coil toeffect the double purpose of pre-heating the charge and simultaneouslycooling the vapors to maintain a proper endpoint on the product passingout at the top of the column through a vapor line '78. Vapors sowithdrawn may be passed through a condenser '79 into an accumulator 80having the usual gas and liquid outlets. Any condensate which may beknocked back by the coil '77 and the fractionating devices at the top ofthe column will be directed by the hood '76 into the annular passagebetween the column or tank 66 and the cylinder 6'7. It is this materialwhich is withdrawn by the pump and passed through the heating coil 64.It is to be observed that all of this material is clean in the sensethat it represents condensate of previously vaporized oil and it istherefore very well suited to destructive distillation or cracking. Ifthe coil '77 is operated at such a temperature as to permit only therelatively light vapors, such as gasoline, to pass through the line '78,it may be found desirable to draw off a certain amount of the materialwithin the annular chamber surrounding the cylinder 6'7 through a line81, either continuously or intermittently. This material may be eitherin the nature of kerosene, gas oil, lubricating stock, or the like.

While several admirable embodiments of the latter. It is particularlyadvantageous, however,

to apply the liquid fuel treating system to a furnace system, or thelike, which is operated at relatively high temperatures so that the fluegases from the latter may be discharged at a relatively hightemperature. The terms employed in the foregoing description are to beconsidered merely as setting forth the nature of the invention and notas imposing any limitations on its scope.

What I claim is:

1. A cyclic process for the treatment and use of a liquid fuel whichcomprises continuously introducing said fuel into a heating zone toeffect partial distillation thereof, removing lighter componentsresulting from said distillation, passing heavier components to burnersin a furnace associated with a primary heat utilization system forheating material other than said fuel maintained at a temperature above2000 F., and cyclically passing intermediate components resulting fromsaid distillation into heat exchange with the flue gases from saidfurnace at a temperature below 1800" F. and back to said heating zone.

2. Apparatus for distilling oil which comprises an outer chamber, aninner chamber, dephlegmating means at the top of said outer chamber,means for feeding fresh oil into said inner chamber, a heating coil,means for withdrawing oil from said outer chamber and'passing the samethrough said heating coil, means for conveying said heated oil to saidinner chamber to evolve vapors therein, and means for directingcondensate from said dephlegmating means to said outer chamber.

3. A process for the treatment and use of a liquid fuel which comprisessubjecting the fuel to distillation, separating the products intolighter and heavier components, passing a portion of the heaviercomponents while hot to burners in a combustion zone associated with aprimary heat utilization system for heating material other than saidfuel, utilizing the waste heat of the flue gases from said zone foreffecting said distillation, and passing a regulated portion of saidheavier components to auxiliary burners to aid said distillation.

4. In apparatus of the class described heating means comprising acombustion zone having burners therein and an economizer section,primary heat absorbing means between said combustion zone and economizersection, a coil in said economizer section, means for passing oilthrough said coil to effect distillation thereof, means for passingmaterial other than oil through said heat absorbing means, means forseparating the oil into lighter and heavier components, means forpassing a portion of said heavier components while hot to said burners,auxiliary burners adapted to supply heat to said economizer section, andmeans for conveying a portion of said heavier components to saidauxiliary burners.

